error: null pointer exception

Question

i am facing an error when i am running the gradle but i dont know what is the problem please help me.

this is the activity code

package com.example.hnnhm.myapplication_new;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.appindexing.Thing;
import com.google.android.gms.common.api.GoogleApiClient;

import org.json.JSONException;
import org.json.JSONObject;

import java.util.HashMap;
import java.util.Map;

public class SignupActivity extends Activity {
    private static final String TAG = SignupActivity.class.getSimpleName();
    private Button btnRegister;
    private Button btnLinkToLogin;
    private EditText inputFullName;
    private EditText inputEmail;
    private EditText inputAge;
    private EditText inputWeight;
    private EditText inputExtra;
    private EditText inputPassword;
    private ProgressDialog pDialog;
    private SessionManager session;
    private SQLiteHandler db;
    /**
     * ATTENTION: This was auto-generated to implement the App Indexing API.
     * See https://g.co/AppIndexing/AndroidStudio for more information.
     */
    private GoogleApiClient client;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_signup);

        inputFullName = (EditText) findViewById(R.id.editText);
        inputEmail = (EditText) findViewById(R.id.email);
        inputAge = (EditText) findViewById(R.id.editText2);
        inputEmail = (EditText) findViewById(R.id.editText3);
        inputExtra = (EditText) findViewById(R.id.editText6);
        inputPassword = (EditText) findViewById(R.id.password);
        btnRegister = (Button) findViewById(R.id.button);
        btnLinkToLogin = (Button) findViewById(R.id.button2);

        // Progress dialog
        pDialog = new ProgressDialog(this);
        pDialog.setCancelable(false);

        // Session manager
        session = new SessionManager(getApplicationContext());

        // SQLite database handler
        db = new SQLiteHandler(getApplicationContext());

        // Check if user is already logged in or not
        if (session.isLoggedIn()) {
            // User is already logged in. Take him to main activity
            Intent intent = new Intent(SignupActivity.this,
                    LoginActivity.class);
            startActivity(intent);
            finish();
        }

        // Register Button Click event
        btnRegister.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                String name = inputFullName.getText().toString().trim();
                String email = inputEmail.getText().toString().trim();
                String password = inputPassword.getText().toString().trim();
                String Age = inputAge.getText().toString().trim();
                String weight = inputWeight.getText().toString().trim();
                String Extra = inputExtra.getText().toString().trim();

                if (!name.isEmpty() && !email.isEmpty() && !password.isEmpty() && !Age.isEmpty()&& !weight.isEmpty()&& !Extra.isEmpty()) {
                    registerUser(name, email, password, Age , weight , Extra);
                } else {
                    Toast.makeText(getApplicationContext(),
                            "Please enter your details!", Toast.LENGTH_LONG)
                            .show();
                }
            }
        });

        // Link to Login Screen
        btnLinkToLogin.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                Intent i = new Intent(getApplicationContext(),
                        LoginActivity.class);
                startActivity(i);
                finish();
            }
        });

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
    }

    /**
     * Function to store user in MySQL database will post params(tag, name,
     * email, password) to register url
     */
    private void registerUser(final String name, final String email,
                              final String password, final String Age, final String weight, final String Extra) {
        // Tag used to cancel the request
        String tag_string_req = "req_register";

        pDialog.setMessage("Registering ...");
        showDialog();

        StringRequest strReq = new StringRequest(Request.Method.POST,
                AppConfig.URL_REGISTER, new Response.Listener<String>() {

            @Override
            public void onResponse(String response) {
                Log.d(TAG, "Register Response: " + response.toString());
                hideDialog();

                try {
                    JSONObject jObj = new JSONObject(response);
                    boolean error = jObj.getBoolean("error");
                    if (!error) {
                        // User successfully stored in MySQL
                        // Now store the user in sqlite
                        String uid = jObj.getString("uid");

                        JSONObject user = jObj.getJSONObject("user");
                        String name = user.getString("name");
                        String email = user.getString("email");
                        String created_at = user
                                .getString("created_at");

                        // Inserting row in users table
                        db.addUser(name, email, uid, Age, weight,Extra);

                        Toast.makeText(getApplicationContext(), "User successfully registered. Try login now!", Toast.LENGTH_LONG).show();

                        // Launch login activity
                        Intent intent = new Intent(
                                SignupActivity.this,
                                LoginActivity.class);
                        startActivity(intent);
                        finish();
                    } else {

                        // Error occurred in registration. Get the error
                        // message
                        String errorMsg = jObj.getString("error_msg");
                        Toast.makeText(getApplicationContext(),
                                errorMsg, Toast.LENGTH_LONG).show();
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e(TAG, "Registration Error: " + error.getMessage());
                Toast.makeText(getApplicationContext(),
                        error.getMessage(), Toast.LENGTH_LONG).show();
                hideDialog();
            }
        }) {

            @Override
            protected Map<String, String> getParams() {
                // Posting params to register url
                Map<String, String> params = new HashMap<String, String>();
                params.put("name", name);
                params.put("email", email);
                params.put("password", password);

                return params;
            }

        };

        // Adding request to request queue
        AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
    }

    private void showDialog() {
        if (!pDialog.isShowing())
            pDialog.show();
    }

    private void hideDialog() {
        if (pDialog.isShowing())
            pDialog.dismiss();
    }

    /**
     * ATTENTION: This was auto-generated to implement the App Indexing API.
     * See https://g.co/AppIndexing/AndroidStudio for more information.
     */
    public Action getIndexApiAction() {
        Thing object = new Thing.Builder()
                .setName("Register Page") // TODO: Define a title for the content shown.
                // TODO: Make sure this auto-generated URL is correct.
                .setUrl(Uri.parse("http://[ENTER-YOUR-URL-HERE]"))
                .build();
        return new Action.Builder(Action.TYPE_VIEW)
                .setObject(object)
                .setActionStatus(Action.STATUS_TYPE_COMPLETED)
                .build();
    }

    @Override
    public void onStart() {
        super.onStart();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client.connect();
        AppIndex.AppIndexApi.start(client, getIndexApiAction());
    }

    @Override
    public void onStop() {
        super.onStop();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        AppIndex.AppIndexApi.end(client, getIndexApiAction());
        client.disconnect();
    }
}

and this is the xml code for the activity

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_signup"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.hnnhm.myapplication_new.SignupActivity">

    <TextView
        android:text="Name:"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:id="@+id/textView3"
        android:textSize="18sp"
        android:textStyle="normal|bold"
        android:textColor="@color/common_google_signin_btn_text_dark_focused"
        android:layout_alignParentStart="true" />

    <TextView
        android:text="Age:"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView4"
        android:layout_below="@+id/editText"
        android:layout_alignParentStart="true"
        android:textStyle="normal|bold"
        android:textSize="18sp"
        android:textColor="@color/common_google_signin_btn_text_dark_focused" />

    <TextView
        android:text="Email:"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText2"
        android:layout_alignParentStart="true"
        android:id="@+id/textView5"
        android:textStyle="normal|bold"
        android:textColor="@color/common_google_signin_btn_text_dark_focused"
        android:textSize="18sp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textEmailAddress"
        android:ems="10"
        android:layout_below="@+id/textView5"
        android:layout_alignEnd="@+id/editText2"
        android:id="@+id/editText4"
        android:text="Your Email"
        android:textColor="@color/common_plus_signin_btn_text_dark_disabled" />

    <TextView
        android:text="Password:"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView6"
        android:textStyle="normal|bold"
        android:textColor="@color/common_google_signin_btn_text_dark_focused"
        android:textSize="18sp"
        android:layout_below="@+id/editText4"
        android:layout_alignParentStart="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:ems="10"
        android:layout_below="@+id/textView6"
        android:layout_alignParentStart="true"
        android:id="@+id/editText5"
        android:text="Password"
        android:textColor="@color/common_plus_signin_btn_text_dark_disabled" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="number"
        android:ems="10"
        android:id="@+id/editText2"
        android:textSize="18sp"
        android:text="Your age"
        android:textColor="@color/common_plus_signin_btn_text_dark_disabled"
        android:layout_below="@+id/textView4"
        android:layout_alignParentStart="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="Your name"
        android:ems="10"
        android:id="@+id/editText"
        android:textSize="18sp"
        android:textColor="@color/common_plus_signin_btn_text_dark_disabled"
        android:layout_below="@+id/textView3"
        android:layout_alignParentStart="true" />

    <TextView
        android:text="Weight:"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView9"
        android:textSize="18sp"
        android:textColor="@color/common_google_signin_btn_text_dark_focused"
        android:textStyle="normal|bold"
        android:layout_below="@+id/editText5"
        android:layout_alignParentStart="true" />

    <Button
        android:text="Login"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/button2"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true"
        android:layout_marginEnd="20dp" />

    <TextView
        android:text="already a member?"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView8"
        android:textAlignment="textStart"
        android:textStyle="normal|bold"
        android:layout_alignParentBottom="true"
        android:layout_toStartOf="@+id/button2" />

    <Button
        android:text="Signup"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/button"
        android:layout_marginStart="11dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentStart="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="Your weight"
        android:ems="10"
        android:layout_below="@+id/textView9"
        android:layout_alignParentStart="true"
        android:id="@+id/editText3"
        android:textColor="@color/common_plus_signin_btn_text_dark_disabled" />

    <TextView
        android:text="allergies and diseases:"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView7"
        android:textStyle="normal|bold"
        android:textSize="18sp"
        android:textColor="@color/common_google_signin_btn_text_dark_focused"
        android:layout_below="@+id/editText3"
        android:layout_alignParentStart="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="and allergies or chronic disease  you have"
        android:ems="10"
        android:id="@+id/editText6"
        android:textSize="18sp"
        android:textColor="@color/common_plus_signin_btn_text_dark_disabled"
        android:layout_below="@+id/textView7"
        android:layout_alignParentStart="true" />

</RelativeLayout>

and this is the error i am getting when running the gradle

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.hnnhm.myapplication_new, PID: 4329
                  java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
                      at com.example.hnnhm.myapplication_new.SignupActivity$1.onClick(SignupActivity.java:86)
                      at android.view.View.performClick(View.java:5637)
                      at android.view.View$PerformClick.run(View.java:22429)
                      at android.os.Handler.handleCallback(Handler.java:751)
                      at android.os.Handler.dispatchMessage(Handler.java:95)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6119)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Disconnected from the target VM, address: 'localhost:8605', transport: 'socket'

you have mapped inputemail twice...your id mapping is incorrect...instead of inputEmail = (EditText) findViewById(R.id.email); you have to pass inputEmail = (EditText) findViewById(R.id.edittext4); — sapan ravani, Apr 22 '17 at 11:46

score 0 · Answer 1 · answered Apr 22 '17 at 11:46

Possible solution could be like:

Check out the gradle version with your previous successful android projects or try re-installing the gradle from scratch if this is the first project.
Clean your project and Re-build the project if there are no issues with the gradle.
Try creating breakpoints on your code where you declare and define variables and run the application on debug mode and check where your variables go NULL.

Because these were the tries I had made on my projects I have worked on.

Might be helpful.

:) PEACE

score 0 · Answer 2 · answered Apr 22 '17 at 11:47

change all :

            String name = inputFullName.getText().toString().trim();
            String email = inputEmail.getText().toString().trim();
            String password = inputPassword.getText().toString().trim();
            String Age = inputAge.getText().toString().trim();
            String weight = inputWeight.getText().toString().trim();
            String Extra = inputExtra.getText().toString().trim();

To

            String name = inputFullName.getText().toString();
            String email = inputEmail.getText().toString();
            String password = inputPassword.getText().toString();
            String Age = inputAge.getText().toString();
            String weight = inputWeight.getText().toString();
            String Extra = inputExtra.getText().toString();

is it false to use the trim method here? – haneen Apr 22 '17 at 12:13 — haneen, Apr 22 '17 at 12:13

score 0 · Accepted Answer · answered Apr 22 '17 at 11:56

0

Change your mappings like this and it will solve your error.
inputFullName = (EditText) findViewById(R.id.editText);
        inputEmail = (EditText) findViewById(R.id.editText4);
        inputAge = (EditText) findViewById(R.id.editText2);
        inputWeight = (EditText) findViewById(R.id.editText3);
        inputExtra = (EditText) findViewById(R.id.editText6);
        inputPassword = (EditText) findViewById(R.id.editText5);

answered Apr 22 '17 at 11:56

sapan ravani

88
9

thank you that works for this error :) – haneen Apr 22 '17 at 12:12

error: null pointer exception

3 Answers3